netcore/System.Private.CoreLib/shared/System/IO/Path.Unix.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 using System.Diagnostics;
   6 using System.Runtime.InteropServices;
   7 using System.Text;
   8
   9 namespace System.IO
  10 {
  11     public static partial class Path
  12     {
  13         public static char[] GetInvalidFileNameChars() => new char[] { '\0', '/' };
  14
  15         public static char[] GetInvalidPathChars() => new char[] { '\0' };
  16
  17         // Expands the given path to a fully qualified path.
  18         public static string GetFullPath(string path)
  19         {
  20             if (path == null)
  21                 throw new ArgumentNullException(nameof(path));
  22
  23             if (path.Length == 0)
  24                 throw new ArgumentException(SR.Arg_PathEmpty, nameof(path));
  25
  26             if (path.Contains('\0'))
  27                 throw new ArgumentException(SR.Argument_InvalidPathChars, nameof(path));
  28
  29             // Expand with current directory if necessary
  30             if (!IsPathRooted(path))
  31             {
  32                 path = Combine(Interop.Sys.GetCwd(), path);
  33             }
  34
  35             // We would ideally use realpath to do this, but it resolves symlinks, requires that the file actually exist,
  36             // and turns it into a full path, which we only want if fullCheck is true.
  37             string collapsedString = PathInternal.RemoveRelativeSegments(path, PathInternal.GetRootLength(path));
  38
  39             Debug.Assert(collapsedString.Length < path.Length || collapsedString.ToString() == path,
  40                 "Either we've removed characters, or the string should be unmodified from the input path.");
  41
  42             string result = collapsedString.Length == 0 ? PathInternal.DirectorySeparatorCharAsString : collapsedString;
  43
  44             return result;
  45         }
  46
  47         public static string GetFullPath(string path, string basePath)
  48         {
  49             if (path == null)
  50                 throw new ArgumentNullException(nameof(path));
  51
  52             if (basePath == null)
  53                 throw new ArgumentNullException(nameof(basePath));
  54
  55             if (!IsPathFullyQualified(basePath))
  56                 throw new ArgumentException(SR.Arg_BasePathNotFullyQualified, nameof(basePath));
  57
  58             if (basePath.Contains('\0') || path.Contains('\0'))
  59                 throw new ArgumentException(SR.Argument_InvalidPathChars);
  60
  61             if (IsPathFullyQualified(path))
  62                 return GetFullPath(path);
  63
  64             return GetFullPath(CombineInternal(basePath, path));
  65         }
  66
  67         private static string RemoveLongPathPrefix(string path)
  68         {
  69             return path; // nop.  There's nothing special about "long" paths on Unix.
  70         }
  71
  72         public static string GetTempPath()
  73         {
  74             const string TempEnvVar = "TMPDIR";
  75             const string DefaultTempPath = "/tmp/";
  76
  77             // Get the temp path from the TMPDIR environment variable.
  78             // If it's not set, just return the default path.
  79             // If it is, return it, ensuring it ends with a slash.
  80             string? path = Environment.GetEnvironmentVariable(TempEnvVar);
  81             return
  82                 string.IsNullOrEmpty(path) ? DefaultTempPath :
  83                 PathInternal.IsDirectorySeparator(path[path.Length - 1]) ? path :
  84                 path + PathInternal.DirectorySeparatorChar;
  85         }
  86
  87         public static string GetTempFileName()
  88         {
  89             const string Suffix = ".tmp";
  90             const int SuffixByteLength = 4;
  91
  92             // mkstemps takes a char* and overwrites the XXXXXX with six characters
  93             // that'll result in a unique file name.
  94             string template = GetTempPath() + "tmpXXXXXX" + Suffix + "\0";
  95             byte[] name = Encoding.UTF8.GetBytes(template);
  96
  97             // Create, open, and close the temp file.
  98             IntPtr fd = Interop.CheckIo(Interop.Sys.MksTemps(name, SuffixByteLength));
  99             Interop.Sys.Close(fd); // ignore any errors from close; nothing to do if cleanup isn't possible
 100
 101             // 'name' is now the name of the file
 102             Debug.Assert(name[name.Length - 1] == '\0');
 103             return Encoding.UTF8.GetString(name, 0, name.Length - 1); // trim off the trailing '\0'
 104         }
 105
 106         public static bool IsPathRooted(string? path)
 107         {
 108             if (path == null)
 109                 return false;
 110
 111             return IsPathRooted(path.AsSpan());
 112         }
 113
 114         public static bool IsPathRooted(ReadOnlySpan<char> path)
 115         {
 116             return path.Length > 0 && path[0] == PathInternal.DirectorySeparatorChar;
 117         }
 118
 119         /// <summary>
 120         /// Returns the path root or null if path is empty or null.
 121         /// </summary>
 122         public static string? GetPathRoot(string? path)
 123         {
 124             if (PathInternal.IsEffectivelyEmpty(path)) return null;
 125
 126             return IsPathRooted(path) ? PathInternal.DirectorySeparatorCharAsString : string.Empty;
 127         }
 128
 129         public static ReadOnlySpan<char> GetPathRoot(ReadOnlySpan<char> path)
 130         {
 131             return PathInternal.IsEffectivelyEmpty(path) && IsPathRooted(path) ? PathInternal.DirectorySeparatorCharAsString.AsSpan() : ReadOnlySpan<char>.Empty;
 132         }
 133
 134         /// <summary>Gets whether the system is case-sensitive.</summary>
 135         internal static bool IsCaseSensitive
 136         {
 137             get
 138             {
 139                 #if PLATFORM_OSX
 140                     return false;
 141                 #else
 142                     return true;
 143                 #endif
 144             }
 145         }
 146     }
 147 }